Palaeontologist Jessica Mitchell of the Steinmann Institute, University of Bonn with the thigh bone of the long-necked dinosaur Apatosaurus. © Photo: Volker Lannert/Uni Bonn

How old were the oldest dinosaurs? This question remains largely unanswered. The natural life span of these long-extinct giants is of interest to scientists, in combination with questions regarding how fast they could grow and how they could obtain sufficient nutrients from their habitat. Palaeontologists at the University of Bonn estimate by means of bone structures whether a particular dinosaur fossil is a young, adult or very old animal. The results have now been published in the journal Paleobiology.